New orientations of in vitro models: why? How?

From the beginning of cell cultures, the aim of all researchers has been to perform culture of a pure population of a particular cell type. However, the monolayer culture (of one type of cell) rapidly showed its limits concerning growth capacity and especially maintenance of the differentiated functions. These findings led to the design of increasingly complex in vitro models. Among them we can distinguish culture onto cellular matrices and into cellular matrices, or tridimensional cell culture. Cocultures in two-compartment dishes or one-compartment dishes, heteroculture, and tissue slices in vitro are other approaches deserving mention. Several examples were reported. Finally, immortalized and transfected cell lines exhibit a different state of complexity.